I am looking for a (used) iSonic to add under my 2010 101 carbon/wood.
I love my 101 with 7.0 and 7.8 Racing Blades, but would like a smaller board to use with 5.6 and 6.3 racing blades.
My weight is 80kg's and I am 1.95m tall, sail mainly on lakes with relatively small chop (Strand Horst in the Netherlands)
I can get a good deal on a used 86, but I am worried its too close to my 101.
Any advice would be welcome.

Both will be a decent change down from your iS101. The iS86 will not be too close to your iS101.

The iS76 has a lot of rocker in the nose c/w the iS86 and would be slightly easier than the iS86 in very gnarly coastal conditions. I remember tatty once saying on the forum that he tested both boards with Kevin P and they concluded that the iS86 was a better "all round" high wind board. Possibly why more iS86 were sold and not so many iS76 were sold.

Personally I loved my iS76 and wished I never sold it, I should have kept it for very rough waters, instead, I now use my W58 (very fast but it does bust my balls in bumpy conditions). Do you know where there is an iS76 in Holland for sale as I have been looking for one god a while.

I would def go for the 86. I had 101, 76 and 86. The 86 has heaps of range and is still highly regarded as an awesome board. Definitely not too close to the 101. Make sure its from 2009 onwards. 2009 and 2010 are the same boards.

I have the Is101 and Is87 and the combination is brilliant. Width is much more important than volume. The Is87 is 56.5 wide the Is101 is 64cm wide, however the Is87 is much narrower in the tail.

I use the Is87 with a 5.7, 6.3 and 7.0 North WARP, the Is101 I use with the 6.3, 7.0 and 7.8 WARP. Although there seems to be an overlap, in reality the boards deal with very different conditions. If the wind is gusty, the Is101 is better for racing as it carries more speed through the gybes, however, if it is choppy and full on then the Is87 is a much nicer board to gybe

In one slalom event this year, we had winds up to 45kts, I was using a 4.5 North ice on the Is87 and it was fantastic, conditions were short chop about 50cm high (ie horrible), I used a 29cm Select Caspar Speed fin, which was surprisingly good in those conditions. I am 174cm tall and 85 KG. I bought the board from a starbord rider, he told me that he wished that he had the Is87 for that event rather than his new Is90 as the Is87 is a better board in really choppy windy conditions